Field of the Invention
The present invention relates to gold pans. More specifically, the present invention relates to a gold pan employing an acentric conical frustum configuration.
Description of the Related Art
The use of gold pans for separating precious materials, including gold, from other minerals in streams and riverbeds is well known. Prospectors have been using gold pans for well over a century. Prospecting for gold is based upon a combination of good fortune and specific principles of materials and material handling. This includes the use of gravity for separation of materials with different specific gravities. Prospectors experienced in the principles of separating heavier materials from lighter materials, will have enhanced prospecting success. And, prospecting success is further enhanced by the ability to more rapidly separate the heavier precious materials from the lighter and worthless materials, called gangue.
The use of gold pans enables prospectors to create an abrasive environment for breaking up loosely bound solids as well as create a swirling action to enhance and speed up separation. Historically, gold pans were made of metal having a concave central portion wherein a slurry of water and material, such as the sand and rock from the bottom of a river bed, would be placed and circulated along the inner surface of the pan. Gold would settle to the bottom, and the lighter materials would be washed out of the pan together with water. Although, it is also known to use dry-panning techniques where no liquid is employed, but similar settling and spilling actions are utilized. Gold pan designs have been improved over the years to assist in the separation process. Modern gold pan designs commonly employ a pan with a flat floor and conical sides that terminate at an upper rim. The proportions of the pans are selected to be reasonable in size and volume for use, transportation, and storage. These can be quantified as an upper rim diameter, depth, and floor diameter. It is known to include stepped indentations, called riffles, in the conical sides of a pan to create recessed areas giving heavier materials a location in which to settle. For example, U.S. Pat. No. 4,162,969 to Lagal, issued Jul. 31, 1979, teaches an apparatus for separating material utilizing a round pan having a concave center portion and steps to assist in material separation. The Lagal teachings enhanced the coarse separation process through the use of riffles having a specific configuration. Once the riffles have been employed, the prospector then transitions operation to a smoother portion of the pan, where a fine separation, fine-panning, process is commenced. Ideally, virtually all of the gangue is washed out of the pan so that only precious materials, usually gold nuggets, remains.
During prospecting operations, a prospector typically places a quantity of ore bearing materials into a gold pan, adds water, and then agitates and swirls the pan to begin the separation process. A coarse separation process is first, where larger materials are spilled, or pushed, off the pan while the heavier materials settle. This is followed by a finer separation process, where the size of the remaining gangue is smaller and the quantity is less as well. The proportions and size of the pan affects the separation techniques during various phases of the separation process. For example, it is desirable to have a proportionately large floor area relative to the rim area to improve separation performance during initial processing, while the prospector is trying to quickly work the high-density gold down through the gangue so that it will collect on the floor. In that case, a pan having a large floor with steep sidewalls provides a more direct and shorter distance for the gold travel in order to reach the floor. In this manner, the gold can travel straight down as opposed to travelling down a long sloped conical side wall. In addition, the proportionately large floor provides a large area for gold to collect and spread out on the bottom of the pan. The ideal concentric shape for this requirement would essentially be a bucket with vertical sidewalls. However, it is also desirable to have a proportionately long sloping conical surface from the rim to the floor for other separating techniques. This configuration provides improved performance during the fine-panning process where the prospector needs as much distance as possible to allow the gold to slowly work its way up the sidewall while washing out the fine gangue, but also so that the gold doesn't wash over the rim. The ideal concentric shape for this requirement would essentially be a simple cone from the rim to the center of the pan, with no floor area at all.
As a practical matter, gold pans are used in remote areas where prospectors believe gold may be present. Thus, prospecting often involves carrying gear to remote locations, conducting prospecting operations over a period of time, and then returning from such locations. This speaks to weight and portability issues. With respect to gold pans, the industry has settled on certain sizes as standards sought by prospectors. The most popular size is a fourteen-inch diameter pan, which may be thought of as a full sized pan. And, there are also ten-inch “back-pack” sized pans. Thus, is it is desirable that improved pans would fit into size categories sought by prospectors. Accordingly, there is a need in the art for an improved gold pan design that improves separation, speed the separation process, and maintains the size and convenience sought by prospectors.